Fluid motor



G. H. GILIVIAN.

FLUID MOTOR. APPLICATION FILED'MAR. 25, 191e. RENEWED MAY 20,1921.

Patented Dec.

i @E uam/ H l l l H l l Patented Dec., 5, 1922.

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GEORGE H. GILMAN, 0F BOSTON, MASSACHUSETTS, ASSIG-NOR TO SULLIVAN MACHINERY COMPANY, A CORPORATION O F IEASSACHUSETTS.

FLUID MOTOR.

Application filed March 25, 1916, Serial No. 86,815. Renewed May 20, 1921. Serial No. 471,157.

To all whom 'it may con/cern.' Y

Be it known that I, GEORGE H. GILMAN, a citizen of the United States, residing at Boston, in the county of Suffolk and State of Massachusetts, have invented certain new and useful improvements in Fluid Motors, of which the following is a full, clear, and exact specification.

My invention relates to iiuid motors, and more particularly to valveless motors of the type having a reciprocatory percussive piston adapted to impart rapidly recurring blows to a drill steel, although my invention is not limited to use in that connection.

It has for its object to provide an improved motor wherein a single charge of a pressure fluid, such as air, acts to reciprocate the piston to and fro in its movement in the cylinder, the forward movement of the piston being much more rapid than the return stroke thereof. More speeiiically, my inven tion has among its objects to increase the power of the piston blow and at the same time balance the piston in an improved manner and reduce the cost of manufacture of the device. rlhese and other objects of my improvement will hereinafter appear.

1n the accompanying drawings, l have for purposes of illustrationshown one embodiment which my invention may assume in practice.

In these drawings,-

Figure 1 is a partial longitudinal developed section of a motor equipped with this form of my improvement, the section being taken on line 1&1 of Figure 3 as to the rear end of the cylinder, and on a line disposed at :i slight angle to the line 1-1 as to the front end of the cylinder, and the piston being shown in its eXtreme rearward position.

Figure Q is a view similar to Figure 1, the section being similarly taken, and the piston being` shown in its eXtreme forward position.

Fiugure 3 is a transverse sectional view taken on line BMS of Figure 1.

Figure a is a transverse sectional view taken on line t-4 of Figure 1.

Figure 5 is a transverse sectional view taken on line 5 5 of Figure 1.

Figure G is a transverse sectional view taken olii line (ie-6 of Figure 1.

In these drawings, I have illustrated a cylinder 1 having a piston chamber 2 therein in which moves a piston member comprising two heads 3 and Ml of the same external diameter, these heads being connected by a reduced portion 5, and the front head l1 being adapted to actuate a tool or steel 6 carried in any suitable housing 7, preferably through an intermediate tappet or anvil 8 of suitable construction seated in the front head 9 of the cylinder.

In my improved construction air is admitted to the piston from a suitable inlet 10 by a controlling` valve 11 of any desired form, which delivers the air through a passage 12 to a receiving chamber 13 formed in the rear head 14 of the cylinder. This chamber, as shown, is provided with a plurality of oppositely disposed radially extending outlets 15 communicating with a plurality of series of parallel passages 16, three being shown herein in each series, extending longitudinally of the cylinder to a point substantially midway of the ends of the latter where these groups of passages communicate with the interior of the cylinder through oppositely disposed ports 17, the latter preferably being so located as to be opposite the reduced portion 5 of the piston when the latter is in its retracted position shown in Figure 1.

This reduced portion thus forms an annular chamber 18 which receives the charge of air admitted from thesupply passages 10, and serves both as a conducting and transporting means for iiuid pressure as will be hereafter evident. kFor the purpose of conducting the pressure fluid from this chamber to the rear end of the cylinderIhave arranged a plurality of ports 20 communicating with va plurality of series of parallel passages 21 formed in the cylinder, preferably of the same number and arrangement as the pas sages 16, and disposed between those passages, but leading rearward and communieating through ports 22 with oppositely disposed transverse passages 23 formed in the rear cylinder head, so that the air may pass inward into a rear pressure chamber Q4 formed in the rear piston head 3, and throughk its pressure `against the rear end of the piston herein including the pressure surface 25 of the chamber, force the piston forward with great rapidity.

Asthe piston moves forward, i. e, toward the right iii Figure 1, its rear head 3 will first close the ports 2O and thereby cut oif the supply of air from the chamber 18 to the passages 21. As the piston moves still 1 further forward, the same head thereon will also close the ports 17 and cut of the air from the passages 16 to the chamber 18. As a result, the air which remains in the chamber 18 after the ports 20 are closed supplemented, i. e. with its pressure somewhat raised by that which has entered the same through the ports 17 in the brief interval before those ports are also closed, is trapped within the chamber 18 and carried bodily forward with the piston, while the air which has acted upon the rear end of the piston is permitted to exhaust, oppositely disposed exhaust openings 26 therefor being cleared by the head 3 as the latter moves forward and preferably shortly after that head has closed the ports 17. As the piston thus moves forward with the air trapped in the chamber V18, and shortly after the ports 17 are closed, ythe chamber 18 surrounding its reduced portion 5 is brought into communication with a plurality of peripherally disposed, radial ports 27, herein three, each communicating with a series of longitudinally extending parallel passages 28. These passages 28 in turn kcommunicate through peripherally disposed ports 29 with the front end of the cylinder` and are obviously put in communication with the supply of air in the chamber 18 shortly before the front piston head d has struck the tappet 8, so that the air admitted through these passages 28 and ports 29 to the front end of the cylinder may act expansively on the front pressure surface 30 of the piston head 4 and thereby drive the latter backward to its initial position, a plurality of exhaust ports 31 being vprovided in the front end of the cylinder to permit the exhaust of this air after it has expanded sufficiently to insurethe return of the piston to its initial position shown in Figure 1.`

Brieiiy reviewing the operation of the motor herein used as an illustration of my invention, the air entering through the ports 17 passes 'through the passages 21 and ports 23 to the rear end of the piston, thereby causing the latter to move to the right as shown in Figure 1, and to trap a charge of air in the annular chamber 18. This charge of air is then carried bodily along with the piston until the chamber 18 is put in communication with the passa-ges 28, whereupon it is permitted to pass to the front end of the piston and act expansively upon the -liront pressure surface 30 thereof to return the piston from the position shown in Figure 2 to the Vposition shown in Figure 1, the air which has previously acted upon the rear pressure surfa-ce of the piston being first exhausted through the port 26, and the air which has acted expansively on the pressure surface 30 being later exhausted through the port 31. Attention is here also directed to the fact that the new charge begins to be admitted to the chamber 18 surrounding the reduced portion 5 of the piston shortly after the ports 27 are closed, but this chamber does not communicate with the rear end of the cylinder until the ports 2O are opened so that a new charge of air at pipe line pressure is put in communication with the rear pressure surfaces of the piston as soon as the ports 20 are cleared by the piston, thus enabling this air to cushion the return stroke of the piston without unduly retarding its rearward travel or causing an undue shortening of the stroke.

It will be noted that in my improved construction, tlie piston heads are of the same external diameter so that the cylinder may be provided with a bore of uniform diameter, and the cost of manufacturing the same and the pistons be thus minimized. Attention is also directed to the fact that through the provision of my improved construction wherein the air is supplied through a plurality of series of ports disposed radially about the piston, the air acts in such a manner on the piston as to balance the latter, and thereby insure even piston movenient and a long piston life. These and other advantages of my improved construction will, however, be apparent to those skilled in the art.

Thile I have in this application specilically described one embodiment which my invention may assume in practice, it is to be understood that, as indicated above, this embodiment of the same is used for purposes of illustration, and that the invention may be modified and embodied in other forms without departing from its spirit, it being my intention to include all such modifications within the scope of the appended claims.

That I claim as new and desire to secure by Letters Patent 1. In a fluid motor. a cylinder, u piston therein having a chamber, said piston being i movable to trap a charge of liuid whollv within the'conlines oll said chamber, and cooperating means for delivering said fiuid lo one end of said cyliiuler; i

2. ln a fluid motor, a cylinder.y a piston therein having a. chamber. said piston being movable to trap and convey a charge of fluid at inlet pressure within the confines of said chamber, and cooperating means forreciprocatingsaid piston in opposite directions communicating with the opposite ends of said cylinder and successive y communicating with said chamber, a portion of said means being adapted to deliver the trapped charge to one end of the cylinder. i

S. In a. liuid motor, a cylii'uler` a piston therein ha ving an intermediate reduced portion whereby a chamber is formed on said piston, said piston beine; movableto trap a charge of iuid within the conlines of said chamber and convey the saine at Aconstant pressure on movement oi' the piston, and cooperating means for reciprocating said piston ,in opposite directions communicating with the opposite ends oil said cylinder and successively communicating with said chamber, a portion of said means being adapted to deliver the trapped charge to one end of the cylinder.

et. il percussive fluidv motor comprising a cylinder of uniform diameter, a piston movable therein having heads oi equal diameter and an intermediate reduced portion, and means including a single set of inlet ports opened and closed 'by said piston tor supplying fluid to said reduced portion and therei'rom successively to the opposite ends of said cylinder.

5. A percussive fluid motor comprising a cylinder of uniform diameter, a piston having a plurality oit heads of equal diameter and an intermediate reduced portion, one of said heads having a pressure chamber therein, and means including ports opening into said cylinder substantiallyv centrally thereoiz and opened and closed by said piston for supplying liuid to said reduced portion and therefrom to the opposite ends oit said cylinder.

3, lu a percussive fluid motor, a cylinder of uniform diameter, and a piston movable therein having heads oit' equal diameter and an intermediate reduced portion, said cylinder having a plurality of parallel supply passages extending from one end thereof and disposed around the same, each passage communicating with said reduced portion through a single port, and a plurality oi passages communicable with said reduced portion, when the reduced portion of the piston is out of communication with said supply ports, and leading to the other end ofV said cylinder.

7. In a percussive fluid motor, a cylinder ot uniformv internal diameter, and a piston having heads on. its opposite ends and an intermediate reduced portion, said cylinder` having a. plurality ot series oit supply pasextending from one end tliereot and vlocated iu the wall thereof, each passage cominunicating with said reduced portion through a single port and a plurality ot series oi', passages communicable with said reduced portion and leading to the other end ot said cylinder, said irst named and last named passages being separated by a distance greater than the length ot thereduced portion ot the piston.

i. ln a percussive iiuid motor, a cylinder, and a piston having heads at its opposite ends and an intermediate reducedportion, said cylinder having an inlet port adjacent its middle and ports leading to the ends ol the cylinder and communicating with the bore thereof on opposite sides ci? said inlet portion, an outlet port communicating therewith and with one end oit said cylinder, said outlet port being spaced longitudinally from said inlet port, and a second outlet port communicating with the opposite end oit said cylinder and spaced longitudinally from inlet port a greater distance than said iirst named outlet port, said ports being successively controlled by said piston during a movement thereoiz in one direction.

l0. ln a percussive `iluid mot-or, a cylinder, and a piston movable therein having a plurality of heads and an intermediate reduced portion, said cylinder having a plurality of inlet ports communicating With said reduced portion, a plurality of outlet passages leading from said reduced portion to one end of said cylinder, and a plurality oi outlet passages leading to the opposite end oi? said cylinder, said first named outletpassages being closed by the piston prior to said inlet ports, and said last named outlet passages being subsequently opened thereby.

1l. In a percussive fluid motor, a cylinder, and a piston movable therein having a plurality of `heads and an intermediate chamber, said cylinder having an inlet port communicating With said intermediate chamber, an outlet port communicating With one end of said cylinder, and a second outlet port communicating with the opposite end ot said cylinder, said ports being so disposed that the inlet port is closed by said piston after the closure of said first named outlet port and before the opening ot said second outlet port thereby.

l2. ln a percussive iiuid motor, a cylinder, and a piston movable therein having a plurality of heads ot equal diameter and au intermediate portion, said cylinder having passagesthereinI con'imunicatii'ig with said intermediate portion in diilerent positions of said piston and with the opposite ends of. said cylinder, and an inlet opened and .closedby said piston, communicating with said intermediate portion prior to the completion of the backward stroke oit said piston, said inlet and intermediate portion bei,

ing adapted to effect the transmission ot operating fluid to both of said operating passages.

i3. ln a percussive fluid motor, a cylin der, and a piston movable therein having a said n ii i) lOO plurality of heads and an intermediate portion, said cylinder having passages therein communicating with said intermediate portion in different positions of said piston and with the opposite ends of said cylinder and an inlet communicating With said intermediate portion prior to the completin of the backward stroke of said piston and after the closure of one of said sets of passages and before the opening' of' the other.

1li. ln a percussive fluid motor, a cylinder having a chambered rear head, a piston movable in said cylinder having heads of equal diameter and an intermediate reduced portion, means including an inlet for supplying Huid from said chambered head to said reduced portion, said means being alternately opened and closed by said piston, and means communicable with said reduced portion and controlled by said piston for delivering` pressure fluid from said inlet to opposite ends of said'cylinder in dierent positions of said piston. l

15. A. `double acting valveless percussive fluid motor comprising a cylinder of constant diameter and a piston having heads of equal diameters, said motor including pressure fluid controlling means providing a single charge of pressure fluid for each cycle of reciprocation of said piston in said cylinder.

16. A valvelessl percussive fluid motor comprising, in combination, a cylinder of constant diameter, a piston therein having heads of equal diameters and an intermediate chamber, initial pressure fluid admission means delivering a predetermined volume of pressure fluid to said intermediate chamber, and conduit means effective after closure of said admission means `to admit said pressure fluid from said intermediate chamber to one end of said cylinder to reverse the direction of' reciprocation of said piston.

17. A valveless pressure fluid motor coinlfrrising a. cylinder of constant diameter und a piston therefor, said cylinder and piston presenting end piston chambers and an intermediate chamber, said motor including pressure fluid distributing `means providing for the transfer in one direction of a predetermined cliarge of pressure fluid in said intermediate chamber to actuate said piston in theopposite direction.

18. A pressure fluid motor comprising a cylinder ofconstant diameter and a piston therefor, said cylinder and piston presenting end piston chambers and an intermediate chamber, said motor including pressure fluid supply means controlled by said piston for admitting pressure uid to said intermediate chamber, conduit means for conducting pressure fluid from said intermediate chamber to one of said end piston chainbers to actuate said piston in one direction,

and means effective after closure of saidconduit means to admit pressure fluid to the other of said end piston chambers;

19. Il double acting valveless percussive fluid motor comprising a cylinder of constant diameter and a piston having heads of equal diameters, said motor including pressure fluid controlling means providing a single charge of pressure fluid for actuating said piston through each cycle of reciprocation of the piston in said cylinder.

20. A. valveless percussive fluid motor comprising, in combination, a cylinder of constant diameter, a piston therein having heads of equal diameter, a lateral fluid inlet 'controlled by said piston, and cooperating pressure fluid delivering means for alternately distributins in opposite directions to the opposite ends of said cylinder a single charge oi pressure fluid during each cycle of reciprocation of said piston in said cylinder.

21. valveless percussive fluid motor comprising, in combination, cylinder of constant diameter, a piston therein having heads of equal diameter, a lateral fluid inlet controlled by said piston, and piston controlled pre fluid distributing means for alternately distributing in opposite diretions to the opposite ends of said cylinder a single charge of pressure fluid during each cycle of reciprocation of said piston in said cylinder.

valveless percussive fluid motor comprising, in combination, a cylinder of constant diameter, a piston therein having heads of. equal diameter and an intermediate chamber. a lateral inlet for admitting fluid to said intermediate chamber, said inlet being opened and closed by said piston, and pressure fluid deliif'ering means for alternately distributing in opposite directions to the opposite ends of said cylinder a single charge oi fluid during each cycle of reciprocntion of said piston in l cylinder.

Q3. .Si valveless percussive 'fluid motor con'ipi'-ising, iu combination, a cylinder of constant diameter` a piston therein having lieuds ol equal dii'zuieters and au intermediate reduced portion, a lateral fluid inlet opened and closed by one of said heads. and pressure fluid delivering means for alternately distributing` in opposite directions to the opposite ends of said cylinder a single charge of pressure fluid during each cycle of reciprocation of said piston 'in said cylinder.

2er.. A valveless fluid pressure motor having a ported cylinder provided with an inlet, and a chambered piston cooperating therewith to conduct the fluid pressure supply for one end of said cylinder, and transport the fluid pressure supply for the other end.

In a valveless fluid pressure motor,

a cylinder, a piston reeiprocable therein,

pressure to the opposite ends of said cylinder including a passage communieating` with said cylinder at one end thereof and also at a point spaced from said end, and a chamber carried by said piston and operative to receive and convey luid at full inlet pressure, said chamber loeing` communicable with said inlet port and said passage only at different times.

In testimony whereof I aHX my signature.

GEORGE H. GLMAN. 

